U.S. patent application number 11/258766 was filed with the patent office on 2006-05-11 for semiconductor memory devices having a dual port mode and methods of operating the same.
Invention is credited to Kee-Won Kwon.
Application Number | 20060098519 11/258766 |
Document ID | / |
Family ID | 36316173 |
Filed Date | 2006-05-11 |
United States Patent
Application |
20060098519 |
Kind Code |
A1 |
Kwon; Kee-Won |
May 11, 2006 |
Semiconductor memory devices having a dual port mode and methods of
operating the same
Abstract
A memory device having a dual port function includes a memory
cell array and a switching unit. The memory cell array has a first
port and a second port. The switching unit assigns first data
received through a data bus to the first port in response to a
leading edge of a clock signal and assigns second data received
through the data bus to the second port in response to a trailing
edge of the clock. Methods of operating memory devices having a
dual port mode are also disclosed.
Inventors: |
Kwon; Kee-Won; (Gyeonggi-do,
KR) |
Correspondence
Address: |
MYERS BIGEL SIBLEY & SAJOVEC
PO BOX 37428
RALEIGH
NC
27627
US
|
Family ID: |
36316173 |
Appl. No.: |
11/258766 |
Filed: |
October 26, 2005 |
Current U.S.
Class: |
365/230.05 |
Current CPC
Class: |
G11C 7/1075
20130101 |
Class at
Publication: |
365/230.05 |
International
Class: |
G11C 8/00 20060101
G11C008/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 10, 2004 |
KR |
10-2004-0091223 |
Claims
1. A memory device comprising: a memory cell array having a first
port and a second port; and a switching unit configured to assign
first data received through a data bus to the first port in
response to a leading edge of a clock signal and configured to
assign second data received through the data bus to the second port
in response to a trailing edge of the clock signal.
2. The memory device of claim 1, wherein, in a write operation, the
switching unit is configured to provide a write command and/or an
address received through a command/address bus to the first port in
response to the leading edge of the clock signal and to assign the
data received through the data bus to the first port in response to
the leading edge of the clock signal.
3. The memory device of claim 1, wherein, in a write operation, the
switching unit is configured to provide a write command and/or an
address received through a command/address bus to the second port
in response to the trailing edge of the clock signal and to assign
the data received through the data bus to the second port in
response to the trailing edge of the clock signal.
4. The memory device of claim 1, wherein, in a read operation, the
switching unit is configured to provide the first data to the data
bus through the first path in response to the leading edge of the
clock signal.
5. The memory device of claim 4, wherein, in a read operation, the
switching unit is configured to provide the second data to the data
bus through the second port in response to the trailing edge of the
clock signal.
6. The memory device of claim 1, wherein the switching unit is
configured to selectively adjust frequencies of assigning the data
to the first port and the second port on the basis of a first
bandwidth and a second bandwidth provided for the first port and
the second port, respectively.
7. The memory device of claim 6, wherein the switching unit is
configured to adjust a first frequency of assigning the data to the
first port to be larger than a second frequency of assigning the
data to the second port, when the first bandwidth is larger than
the second bandwidth.
8. The memory device of claim 1, wherein the switching unit is
configured to receive a control signal indicative of a single port
mode and/or a multi-port mode, and the switching unit is further
configured to assign the data to the first port and the second port
in response to the leading edge and the trailing edge of the clock
signal, respectively, when the control signal is indicative of the
multi-port mode.
9. The memory device of claim 1, further comprising: a first path
through which the first data are transmitted to the first port of
the memory cell array; a second path through which the second data
are transmitted to the second port of the memory cell array;
wherein the first path includes a first command/address buffer and
a first data buffer between the switching unit and the memory cell
array; and wherein the second path includes a second
command/address buffer and a second data buffer between the
switching unit and the memory cell array.
10. A memory device comprising: a switching unit configured to
switch a data bus to a first path in response to a leading edge of
a clock signal and configured to switch the data bus to a second
path in response to a trailing edge of the clock signal; and a
memory cell array coupled to the first path and the second path and
configured to store data received from the first and second
paths.
11. A memory device configured to communicate with a control unit,
the memory device comprising: a command/address bus configured to
receive a command and/or an address from the control unit; a data
bus configured to communicate data between the control unit and the
memory device; a clock signal pin configured to receive a clock
signal from the control unit; a switching unit configured to assign
first data received through the data bus to a first port in
response to a leading edge of the clock signal and to assign second
data received through the data bus to a second port in response to
a trailing edge of the clock signal; a first path through which
first data assigned to the first port are transmitted; a second
path through which second data assigned to the second port are
transmitted; and a memory cell array configured to store the first
data and the second data received respectively through the first
path and the second path.
12. The memory device of claim 11, further comprising a control pin
for receiving a control signal indicative of a single port mode
and/or a dual port mode.
13. A method of operating a memory device in a dual port mode, the
method comprising: assigning first data received through a data bus
to a first port in response to a leading edge of a clock signal and
assigning the second data received through the data bus to a second
port in response to a trailing edge of the clock signal when
requests to access the memory device are received from at least two
controllers; providing first data assigned to the first port to a
memory cell array via a first path; and providing second data
assigned to the second port to the memory cell array via a second
path.
14. The method of claim 13, wherein assigning data to the first
port includes providing a write command and/or an address received
through a command/address bus to the first path in response to the
leading edge of the clock signal in a write operation.
15. The method of claim 13, wherein assigning data to the second
port includes providing a write command and/or an address received
through a command/address bus to the second path in response to the
trailing edge of the clock signal in a write operation.
16. The method of claim 13, wherein assigning data to the first and
second ports includes adjusting frequencies of assigning the data
to the first port and the second port on the basis of a first
bandwidth and a second bandwidth provided respectively at the first
port and the second port.
17. The method of claim 14, wherein assigning data to the first and
second ports includes adjusting a first frequency of assigning the
data to the first port to be larger than a second frequency of
assigning the data to the second port when the first bandwidth is
larger than the second bandwidth.
18. The method of claim 13, further comprising: assigning first
data stored in a memory cell array to a first port in response to a
leading edge of a clock signal and assigning second data stored in
the memory cell array to a second port in response to a trailing
edge of the clock signal when requests to access the memory cell
array are received from at least two controllers; providing the
first data received from the first port to a data bus via a first
path; and providing the second data received from the second port
to the data bus via a second path.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority under 35 U.S.C. .sctn. 119
to Korean Patent Application No. 10-2004-0091223 filed on Nov. 10,
2004, the disclosure of which is hereby incorporated herein by
reference as if set forth in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to semiconductor memory
devices, and more particularly, to semiconductor memory devices
having a dual port mode and methods of operating memory devices in
a dual port mode.
BACKGROUND
[0003] Various sub-blocks of a central processing unit (CPU) used
in mobile computing devices such as, for example, mobile
telephones, personal digital assistants (PDAs), portable music
players, and the like, may require access to a memory device.
[0004] Specifically, in order to perform a large number of
functions efficiently, the CPU of a mobile computing device may
include various associated sub-blocks, such as a baseband
processing block, a game-related processing block, a camera-related
processing block, a music-related processing block, and/or other
processing blocks. In order to simultaneously perform two or more
functions, such as to simultaneously perform a music function and a
game function, and/or to simultaneously perform a call function and
a camera function, the corresponding sub-blocks may need to
simultaneously access a memory device.
[0005] A memory device may be designed to have multiple ports so as
to accommodate multiple memory accesses, thereby enhancing the
overall system performance. Specifically, when two sub-blocks
simultaneously access the memory device, the memory device may have
I/O data pins and address/command pins for each of the two
sub-blocks.
[0006] In that case, the total number of I/O pins coupled to the
memory device may increase and the power consumption of the system
may increase accordingly.
SUMMARY
[0007] A memory device according to some embodiments of the
invention includes a switching unit configured to assign data
received through a data bus to a first port in response to a
leading edge of a clock signal and configured to assign the
received data to a second port in response to a trailing edge of
the clock signal. A memory device according to embodiments of the
invention further includes a first path through which first data
assigned to the first port are transmitted, a second path through
which second data assigned to the second port are transmitted, and
a memory cell array configured to store the first data and the
second data transmitted respectively through the first path and the
second path.
[0008] To perform a write operation, the switching unit may be
configured to provide a write command and/or an address received
through a command/address bus to the first path in response to the
leading edge of the clock signal and to assign the data received
through the data bus to the first port in response to the leading
edge of the clock signal. The switching unit may be configured to
provide a write command and/or an address received through a
command/address bus to the second path in response to the trailing
edge of the clock signal and to assign the data received through
the data bus to the second port in response to the trailing edge of
the clock signal.
[0009] To perform a read operation, the switching unit may be
configured to provide the first data to the data bus through the
first path in response to the leading edge of the clock signal. The
switching unit may be further configured to provide the second data
to the data bus through the second path in response to the trailing
edge of the clock signal.
[0010] In some embodiments of the invention, the switching unit may
be configured to selectively adjust frequencies of assigning the
data to the first port and the second port on the basis of a first
bandwidth and a second bandwidth provided for the first port and
the second port, respectively. The switching unit may further be
configured to adjust a first frequency of assigning the data to the
first port to be larger than a second frequency of assigning the
data to the second port, when the first bandwidth is larger than
the second bandwidth.
[0011] The switching unit may be configured to receive a control
signal indicative of a single port mode and/or a dual port mode,
and the switching unit may be further configured to assign the data
to the first port and the second port in response to the leading
edge and the trailing edge of the clock signal, respectively, when
the control signal is indicative of the dual port mode.
[0012] A memory device according to further embodiments of the
invention includes a switching unit configured to switch a data bus
to a first path in response to a leading edge of a clock signal and
configured to switch the data bus to a second path in response to a
trailing edge of the clock signal, and a memory cell array coupled
to the first path and the second path and configured to store the
data received from the first and second paths.
[0013] According to some embodiments of the invention, a memory
device configured to communicate with a control unit is provided.
In particular, the memory device includes a command/address bus
configured to receive a command and/or an address from the control
unit, a data bus configured to communicate data with the control
unit, a clock signal pin configured to receive a clock signal from
the control unit, and a switching unit configured to assign data
received through the data bus to a first port in response to a
leading edge of the clock signal and to assign the received data to
a second port in response to a trailing edge of the clock signal.
The device further includes a first path through which first data
assigned to the first port are transmitted, a second path through
which second data assigned to the second port are transmitted, and
a memory cell array configured to store the first data and the
second data received respectively through the first path and the
second path.
[0014] The memory device may further include a control pin for
receiving a control signal indicative of a single port mode and/or
a dual port mode.
[0015] Methods of operating a memory device in a dual port mode
according to some embodiments of the invention include assigning
data received through a data bus to a first port in response to a
leading edge of a clock signal and assigning the received data to a
second port in response to a trailing edge of the clock signal when
requests to access the memory device are received from at least two
controllers, providing first data assigned to the first port to a
memory cell array via a first path, and providing second data
assigned to the second port to the memory cell array via a second
path.
[0016] Assigning data to the first port may include providing a
write command and/or an address received through a command/address
bus to the first path in response to the leading edge of the clock
signal in a write operation. Assigning data to the second port may
include providing a write command and/or an address received
through a command/address bus to the second path in response to the
trailing edge of the clock signal in a write operation.
[0017] In particular embodiments of the invention, assigning data
to the first and second ports may include adjusting frequencies of
assigning the data to the first port and the second port on the
basis of a first bandwidth and a second bandwidth respectively at
the first port and the second port. Assigning data to the first and
second ports may include adjusting a first frequency of assigning
the data to the first port to be larger than a second frequency of
assigning the data to the second port when the first bandwidth is
larger than the second bandwidth.
[0018] Methods of operating a memory device in a dual port mode
according to further embodiments of the invention include assigning
first data stored in a memory cell array to a first port in
response to a leading edge of a clock signal and assigning second
data stored in the memory cell array to a second port in response
to a trailing edge of the clock signal when requests to access the
memory cell array are received from at least two controllers,
providing the first data received from the first port to a data bus
via a first path, and providing the second data received from the
second port to the data bus via a second path.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The accompanying drawings, which are included to provide a
further understanding of the invention and are incorporated in and
constitute a part of this application, illustrate certain
embodiment(s) of the invention. In the drawings:
[0020] FIG. 1 is a block diagram of a memory device having a dual
port function according to some embodiments of the present
invention;
[0021] FIG. 2 is a block diagram illustrating a memory device
having a dual port function and an associated control unit
according to some embodiments of the present invention;
[0022] FIG. 3 is a block diagram illustrating a memory device
having a dual port function and an associated control unit
according to further embodiments of the present invention;
[0023] FIG. 4 is a timing diagram illustrating operations of the
memory device of FIG. 1 according to some embodiments of the
present invention;
[0024] FIG. 5 is a timing diagram illustrating operations of the
memory device of FIG. 1 according to further embodiments of the
present invention;
[0025] FIG. 6 is a block diagram illustrating operations of
accessing a memory device having a dual port function according to
some embodiments of the present invention; and
[0026] FIG. 7 is a block diagram illustrating a memory device
having a dual port function and an associated control unit
according to further embodiments of the present invention.
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0027] Hereinafter, embodiments of the present invention will be
described with reference to the accompanying drawings.
[0028] It will be understood that, although the terms first,
second, etc. may be used herein to describe various elements, these
elements should not be limited by these terms. These terms are only
used to distinguish one element from another. For example, a first
element could be termed a second element, and, similarly, a second
element could be termed a first element, without departing from the
scope of the present invention. As used herein, the term "and/or"
includes any and all combinations of one or more of the associated
listed items.
[0029] It will be understood that when an element is referred to as
being "connected" or "coupled" to another element, it can be
directly connected or coupled to the other element or intervening
elements may be present. In contrast, when an element is referred
to as being "directly connected" or "directly coupled" to another
element, there are no intervening elements present.
[0030] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the invention. As used herein, the singular forms "a", "an" and
"the" are intended to include the plural forms as well, unless the
context clearly indicates otherwise. It will be further understood
that the terms "comprises", "comprising,", "includes" and/or
"including", when used herein, specify the presence of stated
features, integers, steps, operations, elements, and/or components,
but do not preclude the presence or addition of one or more other
features, integers, steps, operations, elements, components, and/or
groups thereof.
[0031] Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which this
invention belongs. It will be further understood that terms, such
as those defined in commonly used dictionaries, should be
interpreted as having a meaning that is consistent with their
meaning in the context of this specification and the relevant art
and will not be interpreted in an idealized or overly formal sense
unless expressly so defined herein.
[0032] A semiconductor memory device having a dual port function
according to some embodiments of the present invention may be
advantageously employed in electronic devices that include a
plurality of logic circuits that are mounted on a single
semiconductor chip and may request simultaneous access to a memory.
Some embodiments of the invention may be particularly useful in
devices having multiple processing blocks, such as, for example
mobile telephones and/or other mobile computing devices.
[0033] FIG. 1 is a block diagram of a memory device having a dual
port function according to some embodiments of the present
invention.
[0034] Referring to the embodiments of FIG. 1, a memory device 100
includes a data (DQ) bus 101, a command/address (CA) bus 103, a
clock (CLK) pin 105, and a control (S/D SEL) pin 107. In some
embodiments, the data bus 101 and/or the command/address bus 103
may include a serial data bus and/or a parallel data bus. In
particular embodiments, the data bus 101 may include an n-line
parallel data bus and the command/address bus 103 may include an
i-line parallel data bus as indicated in FIG. 2. The pin and/or bus
lines described herein, and the terminology used to describe such
pin and/or bus lines, are provided as examples only. Other pins
and/or bus lines may be used to communicate data and/or command
information to/from the memory device 100.
[0035] In performing a write operation and/or a read operation,
data may be communicated between the memory device 100 and at least
one external control unit through the DQ bus 101.
[0036] Various commands associated with a read operation and/or a
write operation and/or an address signal may be transmitted from
the external control unit to the memory device 100 through the CA
bus 103.
[0037] A clock signal is transmitted to the memory device 100
through the CLK pin 105.
[0038] The memory device 100 according to an example embodiment of
the present invention has a structure similar to the structure of a
single port memory device except that the memory device 100 may
receive a control signal S/D SEL indicative of a given port mode,
for example, a single port mode, a dual port mode, etc., through
the S/D SEL pin 107.
[0039] The memory device 100 may include, for example, a DRAM
(Dynamic Random Access Memory), an SRAM (Static RAM), a flash
memory, and/or other types of memory devices.
[0040] The external control unit may include, for example, a
baseband block for processing baseband signals, a game-related
processing block (hereinafter simply referred to as "game block"),
a camera-related processing block (hereinafter simply referred to
as "camera block"), a music-related processing block (hereinafter
simply referred to as "music block"), and/or other types of
processing blocks.
[0041] For example, in order to simultaneously perform a music
function and a game function, the music block and the game block
may simultaneously request access to the memory device 100.
Likewise, in order to simultaneously perform a call function and a
camera function, the baseband block and the camera block may
simultaneously request access to the memory device 100.
[0042] In such a situation, commands, addresses, data, and clocks
may be transmitted from two associated blocks (e.g., the music
block and the game block) to the memory device 100 through one DQ
bus 101, one CA bus 103 and one CLK pin 105, and/or data may be
transmitted from the memory device 100 to the blocks through one DQ
bus 101.
[0043] FIG. 2 is a block diagram illustrating a memory device 100
having a dual port function and an associated control unit 200
according to some embodiments of the present invention.
[0044] Referring to the embodiments of FIG. 2, the control unit 200
includes a first controller 210, a second controller 230, and a
first switching unit 220. A memory device 100 includes a memory
cell array 110, a second switching unit 120, a first path 130, and
a second path 140. The first path 130 includes a first CA buffer
(CA BUFFER 1) 132 and a first DQ buffer (DQ BUFFER 1) 134, and the
second path 140 includes a second CA buffer (CA BUFFER 2) 142 and a
second DQ buffer (DQ BUFFER 2) 144. The control unit 200 may
include more than two controllers, and the memory device 100 may
include more than two paths to provide a memory device operating
substantially similar to a memory device having three or more
ports. However, the discussion of the embodiments of FIG. 2 is
directed to a memory device having a dual-port mode for purposes of
brevity.
[0045] The first switching unit 220 receives a request for access
to the memory device 100 from at least one of the first controller
210 and/or the second controller 230. When the first switching unit
220 receives simultaneous memory access requests from both the
first controller 210 and the second controller 230 (e.g. if the
first controller 210 makes a request for memory access while the
switching unit 220 is processing a request for memory access from
the second controller 220, or vice-versa, or if memory requests are
initiated by the first controller 210 and the second controller 220
in the same clock cycle), the first switching unit 220 generates
and provides a control signal S/D SEL indicating, for example, a
dual port mode to the second switching unit 120 through an S/D SEL
pin 107. Unless simultaneous memory access requests are received
from the first controller 210 and the second controller 230, the
first switching unit 220 generates and provides a control signal
S/D SEL indicating a single port mode to the second switching unit
120 through the S/D SEL pin 107.
[0046] The first switching unit 220 may be implemented, for
example, as a multiplexer and/or a demultiplexer.
[0047] The control unit 200 may be a central processing unit (CPU)
of, for example, a computing device such as a mobile phone. The
first controller (or first processor) 210 or the second controller
(or second processor) 230 may be any one of a baseband block for
processing baseband communication signals, a game block for
processing associated game function, a camera block for processing
associated camera function, a music block for processing associated
music function, etc.
[0048] The control unit 200 transmits commands and/or addresses
needed to access the memory device 100 from the first controller
210 and the second controller 230 to the memory device 100 through
a CA bus 103. In addition, the control unit 200 transmits data
generated from the first controller 210 and the second controller
230 to the memory device 100 through a DQ bus 101.
[0049] The second switching unit 120 receives data,
commands/addresses, clocks, and control signals from the control
unit 200 respectively through the DQ bus 101, the CA bus 103, a CLK
pin 105, and the S/D SEL pin 107. When the control signal S/D SEL
indicates the single port mode, the second switching unit 120
latches and provides the data, the command and/or the address bits
to the memory cell array 110 through the first path 130 or the
second path 140 in response to a rising edge (or a falling edge) of
the clock signal.
[0050] When the control signal S/D SEL indicates the dual port
mode, the second switching unit 120 latches and assigns the data,
the command and/or the address bits to one of a first port 135
and/or a second port 145 through the first path 130 and the second
path 140, respectively. For example, the data, command and/or
address bits may be assigned to a first port 135 and transmitted
through the first path 130 to the memory cell array 110 in response
to a rising edge (or a falling edge) of the clock signal. In
addition, the data, the command and/or the address bits may be
assigned to a second port 145 and transmitted through the second
path 140 to the memory cell array 110 in response to a falling edge
(or a rising edge) of the clock signal.
[0051] Specifically, in a write operation, when the control signal
S/D SEL indicates the dual port mode, the second switching unit 120
latches and provides write commands and addresses received through
the CA bus 103 to the first CA buffer (CA BUFFER 1) 132 in response
to a rising edge (or a falling edge) of the clock signal, and
provides data received through the DQ bus 101 to the first DQ
buffer (DQ BUFFER 1) 134 in response to a rising edge (or a falling
edge) of the clock signal. In addition, in a write operation, when
the control signal S/D SEL indicates the dual port mode, the second
switching unit 120 latches and provides write commands and
addresses received through the CA bus 103 to the second CA buffer
142 (CA BUFFER 2) in response to a falling edge (or a rising edge)
of the clock signal, and provides data received through the DQ bus
101 to the second DQ buffer (DQ BUFFER 2) 144 in response to a
falling edge (or a rising edge) of the clock signal.
[0052] The second switching unit 120 may adjust the frequencies of
assigning the data to the first and second ports 135, 145, on the
basis of the bandwidths required at the first and second ports 135,
145. For example, when the bandwidth required at the first port 135
is larger than the bandwidth required at the second port 145, the
second switching unit 120 may adjust the frequency of assigning the
data to the first port 135 to be larger than the frequency of
assigning the data to the second port 145.
[0053] Specifically, in a read operation, when the control signal
S/D SEL indicates the dual port mode, the second switching unit 120
may read data from the memory cell array 110 through the first DQ
buffer 134 of the first path 130 corresponding to the first port
135, and may output the read data to the DQ bus 101 in response to
a rising edge (or a falling edge) of the clock signal. In addition,
in the read operation, when the control signal S/D SEL indicates
the dual port mode, the second switching unit 120 may read data
from the memory cell array 110 through the second DQ buffer 144 of
the second path 140 corresponding to the second port 145, and may
output the read data to the DQ bus 101 in response to a falling
edge (or a rising edge) of the clock signal.
[0054] The first controller 210 and the second controller 230 may
request to write data and/or to read data to/from the memory device
100 simultaneously. Alternatively, the first controller 210 may
request to write data to the memory device 100, while the second
controller 230 requests to read data from the memory device 100, or
vice-versa.
[0055] FIG. 3 is a block diagram illustrating a memory device
having a dual port function and an associated control unit
according to further embodiments of the present invention.
[0056] As illustrated in FIG. 3, unlike the example embodiment
illustrated in FIG. 2, a memory device 100A for performing the dual
port function may not include the S/D SEL pin 107 for receiving the
control signal S/D SEL indicating the single port mode or the dual
port mode.
[0057] FIG. 4 is a timing diagram illustrating operations of the
memory device in FIG. 1 according to some embodiments of the
present invention.
[0058] Referring to FIG. 4, data (or command/address bits) may be
assigned alternately to a first port P0 and a second port P1 in
response to a falling edge and a rising edge of the clock CLK,
respectively.
[0059] For example, the dual port function may be implemented by
assigning data (or command/address bits) to the first port P0 in
response to a falling edge of a clock while assigning data (or
command/address bits) to the second port P1 in response to a rising
edge of the clock.
[0060] Specifically, in a write operation, data having logic "0"
may be output from the DQ bus 101 to the second port P1 during a
period t1 in response to the rising edge of the clock CLK (arrow
41), and data having logic "1" may be output from the DQ bus 101 to
the first port P0 during a period t2 in response to the falling
edge of the clock CLK (arrow 42).
[0061] In a read operation, data having logic "0" may be output
from the second port P1 to the DQ bus 101 during the period t1 in
response to the rising edge of the clock CLK, and data having logic
"1" may be output from the first port P0 to the DQ bus 101 during
the period t2 in response to the falling edge of the clock CLK.
[0062] In a similar manner, the command (or the address) received
from the CA bus 103 may be assigned to the first and/or second
ports P0 and P1.
[0063] FIG. 5 is a timing diagram illustrating operations of the
memory device in FIG. 1 according to further embodiments of the
present invention.
[0064] Referring to FIG. 5, when the bandwidth required at the
second port P1 is, for example, three times the bandwidth required
at the first port P0, data (or command/address bits) may be
assigned, for example, to the first and second ports P0 and P1 in
an order that follows the pattern P1-P1-P1-P0-P1-P1-P1-P0 in
response to the falling and rising edges of the clock signal CLK.
When the bandwidth required at the second port P1 is, for example,
two times the bandwidth required at the first port P0, data may be
assigned, for example, to the ports in an order that follows the
pattern P1-P1-P0-P1-P1-P0 in response to the falling and rising
edges of the clock signal CLK.
[0065] Specifically, in a write operation, when data (or
command/address bits) are assigned to the first and second ports P0
and P1 in an order that follows the pattern
P1-P1-P1-P0-P1-P1-P1-P0, data respectively having logic "0", "1"
and "1" may be sequentially output from the DQ bus 101 to the
second port P1 during corresponding clock periods t1, t2 and t3
responsive to consecutive rising, falling and rising edges of the
clock CLK. Data having logic "0" may be output from the DQ bus 101
to the first port P0 during a clock period t4 responsive to the
next falling edge of the clock CLK.
[0066] In the read operation, data (or command/address bits) may be
read from the ports in an order that follows the pattern
P1-P1-P1-P0-P1-P1-P1-P0, and data respectively having logic "0",
"1" and "1" may be sequentially output from the second port P1
during the clock periods t1, t2 and t3. Also, data having logic "0"
may be output from the first port P0 to the DQ bus 101 during the
clock period t4.
[0067] FIG. 6 is a block diagram illustrating operations of
accessing a memory device having a dual port function according to
some embodiments of the present invention.
[0068] Referring to the embodiments of FIG. 6, when the first
controller 210 and the second controller 230 simultaneously request
access to the memory device 100 to perform a write operation, the
memory device 100 may receive data (or command/address bits) from
the first controller 210 through the DQ bus 101 (or the CA bus 103)
in response to the falling edge of the clock CLK to store the
received data in the memory cell array 110 via the first path 130.
And, the memory device 100 may receive data (or command/address
bits) from the second controller 230 through the DQ bus 101 (or the
CA bus 103) in response to the rising edge of the clock CLK to
store the received data in the memory cell array 110 via the second
path 140.
[0069] Similarly, when the first controller 210 and the second
controller 230 simultaneously request an access to the memory
device 100 to perform a read operation, the memory device 100 may
output data read from the memory cell array 110 through the first
path 130 to the DQ bus 101 (or the CA bus 103) in response to the
falling edge of the clock. The read data may be transferred to the
first controller 210. And, the memory device 100 may output data
read from the memory cell array 110 through the second path 140 to
the DQ bus 101 (or the CA bus 103) in response to the rising edge
of the clock. The read data may be transferred to the second
controller 230.
[0070] FIG. 7 is a block diagram illustrating a memory device
having a dual port function and a control unit thereof according to
further embodiments of the present invention.
[0071] Referring to FIG. 7, a control unit 700 includes a first
controller block 710, a second controller block 720, . . . , an Nth
controller block 750. The controller blocks 710, 720, . . . , 750
each may include two controllers, e.g., 712 and 714, 722 and 724, .
. . 752 and 754, respectively. For example, a respective controller
may correspond to a baseband processing block, a game processing
block, a camera processing block, a music processing block, and/or
another type of processing block.
[0072] A selector 790 receives a memory access request from the
respective controllers 712 and 714, 722 and 724, . . . , 752 and
754 and transmits data and commands/addresses from the requesting
controllers to the memory device 100 respectively through the DQ
bus 101 and/or the CA bus 103.
[0073] In some embodiments, a pair of two controllers having a high
possibility of simultaneously accessing the memory device 100 may
be paired in one controller block. For example, a controller for
control of processing associated with a music block and another
controller for control of processing associated with a camera may
constitute one controller block. Alternatively or in addition, a
controller for control of processing associated with a game block
and another controller for control of processing associated with a
music block may constitute one controller block.
[0074] The structure and operation of the memory device 100 of FIG.
7 may be the same as those in the foregoing embodiments and thus a
detailed description thereof may be omitted for conciseness.
[0075] As described above, when at least two memory access requests
are simultaneously received, at least two ports may be respectively
assigned in response to the rising edge and the falling edge of a
clock signal, respectively, to provide a multi port function, e.g.,
a dual port function, according to some embodiments of the present
invention. Accordingly, in some embodiments of the invention, a
dual port function of a memory device may be implemented without
increasing the number of the pins of the memory device as compared
to a conventional memory device. Thus, the power consumption of a
memory device according to some embodiments of the invention may be
reduced.
[0076] While the present invention has been described with
reference to the example embodiments, it will be apparent to those
skilled in the art that various changes and modifications may be
made without departing from the spirit and scope of the invention
as defined in the following claims.
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